Component with a reinforcing plating

ABSTRACT

A component, in particular a rotor blade of a gas turbine, having a blade tip plating, the plating including a cover layer that is formed of abrasive particles embedded in a metallic matrix material, and the cover layer being applied onto a surface of the component with the intermediate situation of a metallic bonding layer, wherein the metallic bonding layer is fashioned as a bonding layer applied to the component by high-speed flame spraying, and that the metallic matrix material of the cover layer is galvanically deposited.

The present invention relates to a component, in particular a gasturbine component such as a turbine rotor blade, having a plating, inparticular a blade tip plating, as recited in the preamble of Claim 1.

Turbomachines, such as gas turbines, generally have a plurality ofrotating rotor blades and a plurality of stationary guide blades, therotor blades rotating together with a rotor and the rotor blades andguide blades being enclosed in a stationary housing. In order to improveperformance, it is important to optimize all components and subsystems,including what are known as sealing systems.

In turbomachines, a particular problem is the maintenance of a minimumgap between the rotating rotor blades and the stationary housing of ahigh-pressure compressor. This is because high-pressure compressorsexhibit the highest absolute temperatures and temperature gradients,which makes it difficult to maintain the gap between the rotating rotorblades and the stationary housing. Inter alia, another reason for thisis that compressor rotor blades do not have shrouds as are used inturbine rotor blades.

As just mentioned, rotor blades in a compressor do not have shrouds.Therefore, ends or tips of the rotor blades are exposed to directfrictional contact with the stationary housing, in what is called bladerubbing. Such rubbing of the tips of the rotor blades in the housing iscaused by manufacturing tolerances during the setting of a minimumradial gap. Because the frictional contact of the tips of the rotorblades wears material away from them, an undesired enlargement of thegap can result around the entire periphery of the housing and rotor. Inorder to avoid this, it is known from the prior art to plate the ends ortips of the rotor blades with a hard coating or with abrasive particles.Two different types of blade tip platings are known from the prior art,namely, on the one hand, platings of a ceramic material or, on the otherhand, platings of abrasive particles. The present invention relates to aplating, in particular a blade tip plating, of a component, inparticular a gas turbine rotor blade, with abrasive particles.

U.S. Pat. No. 6,194,086 B1 discloses a rotor blade of a gas turbinehaving a blade tip plating in which the blade tip plating comprises acover layer that is made of abrasive particles embedded in a metallicmatrix material. The cover layer made up of the abrasive particlesembedded in the metallic matrix material is applied onto the tip of arotor blade that is to be plated with the interposition of a metallicbonding layer. The metallic bonding layer is fashioned as a LPPS layer,and is accordingly applied to the component using low-pressure plasmaspraying. The disadvantage of such LPPS bonding layers is that inparticular at high operating temperatures of up to 1200° C. they havelow mechanical adhesion to the blade tip, so that during operation theblade tip plating can flake off.

Against this background, the present invention is based on the problemof creating a new type of component having a plating. This problem issolved by a component as recited in Claim 1. According to the presentinvention, the metallic bonding layer is fashioned as a bonding layerthat is applied to the component using high-speed flame spraying, themetallic matrix material of the cover layer being galvanicallydeposited.

According to the present invention, the bonding layer is applied to thecomponent using high-speed flame spraying. In this way, the platingadheres to the component better than is the case given the use of LPPSbonding layers. The blade tip plating of the component accordingly hasbetter mechanical bonding, in particular at high operating temperatures.

Preferred further developments of the present invention result from thesubclaims and from the following description. Exemplary embodiments ofthe present invention are explained in more detail on the basis of thedrawing, without being limited thereto.

FIG. 1 shows a schematized cross-section of a plating applied to acomponent.

The present invention relates to a plated component, in particular arotor blade of a gas turbine provided with a blade tip plating. Therotor blade of the gas turbine is preferably realized as a high-pressurecompressor rotor blade.

FIG. 1 shows a highly schematized cross-section of a blade tip 10 of arotor blade, blade tip 10 of the rotor blade having a blade tip plating11.

Blade tip plating 11 has at least two layers, namely an outer coverlayer 12 and an inner bonding layer 13. In the exemplary embodimentshown in FIG. 1, cover layer 12 is applied onto blade tip 10 via bondinglayer 13. Additional layers may be present between cover layer 12 andbonding layer 13.

According to FIG. 1, cover layer 12 is formed by abrasive particles 14that are embedded in a metallic matrix material 15. Bonding layer 13 isrealized as a metallic bonding layer. Metallic bonding layer 13 andmetallic matrix material 15 of cover layer 12 are each made of a MCrAlYmaterial.

According to the present invention, metallic bonding layer 13 isfashioned as a bonding layer applied to the component using high-speedflame spraying (HVOF). Due to the application of bonding layer 13 usinghigh-speed flame spraying, said bonding layer is very strong and has lowporosity, so that it adheres well to blade tip 10. Metallic matrixmaterial 15 of cover layer 12 is deposited galvanically. Abrasiveparticles 14 are embedded therein that are preferably formed as hardmaterial particles made of cubic boron nitride.

As already mentioned, metallic matrix material 15 of cover layer 12, andmetallic bonding layer 13, are each made of a MCrAlY material,preferably having the following composition:

14-22% by weight chromium (Cr),6-14% by weight cobalt (Co),4-9% by weight aluminum (Al),5-8% by weight tantalum (Ta),1-3% by weight rhenium (Re),0.5-1% by weight hafnium (Hf),0.5-1.5% by weight silicon (Si),0.3-1% by weight yttrium (Y),remainder nickel.

The following composition of the MCrAlY material is particularlypreferred:

18% by weight chromium,10% by weight cobalt (Co),6.5% by weight aluminum (Al),6% by weight tantalum (Ta),2% by weight rhenium (Re),0.5% by weight hafnium (Hf),1% by weight silicon (Si),0.3% by weight yttrium (Y),remainder nickel.

According to the present invention, in this way a rotor blade isprovided having a blade tip plating, the plating having a high-speedflame-sprayed bonding layer that creates the bond of blade tip plating11 to blade tip 10, and high-speed flame-sprayed bonding layer 13 havinghigh mechanical load capacity, in particular at high operatingtemperatures. Bonding layer 13 bears cover layer 12, which is formed ofabrasive particles 14 embedded in metallic matrix material 15, metallicmatrix material 15 of cover layer 12 being galvanically deposited.

1. A component, in particular a rotor blade of a gas turbine,comprising: a blade tip plating, said plating including a cover layerthat is formed of abrasive particles embedded in a metallic matrixmaterial, and the cover layer being applied onto a surface of thecomponent with the intermediate situation of a metallic bonding layer,wherein the metallic bonding layer is fashioned as a bonding layerapplied to the component by high-speed flame spraying, and that themetallic matrix material of the cover layer is galvanically deposited.2. The component as recited in claim 1, wherein the metallic matrixmaterial of the cover layer is made of a MCrAlY material,or includes aMCrAlY material.
 3. The component as recited in claim 2, wherein themetallic matrix material of the cover layer is made of a MCrAlY materialand has the following composition: 14-22% by weight chromium (Cr), 6-14%by weight cobalt (Co), 4-9% by weight aluminum (Al), 5-8% by weighttantalum (Ta), 1-3% by weight rhenium (Re), 0.5-1% by weight hafnium(Hf), 0.5-1.5% by weight silicon (Si), 0.3-1% by weight yttrium (Y), theremainder being in nickel.
 4. The component as recited in claim 3,wherein the MCrAlY material has the following composition: 18% by weightchromium (Cr), 10% by weight cobalt (Co), 6.5% by weight aluminum (Al),6% by weight tantalum (Ta), 2% by weight rhenium (Re), 0.5% by weighthafnium (Hf), 1% by weight silicon (Si), 0.3% by weight yttrium (Y), theremainder being nickel.
 5. The component as recited in claim 1, whereinthe metallic bonding layer is made of a MCrAlY material and has thefollowing composition: 14-22% by weight chromium (Cr), 6-14% by weightcobalt (Co), 4-9% by weight aluminum (Al), 5-8% by weight tantalum (Ta),1-3% by weight rhenium (Re), 0.5-1% by weight hafnium (Hf), 0.5-1.5% byweight silicon (Si), 0.3-1% by weight yttrium (Y), the remainder beingnickel.
 6. The component as recited in claim 5, wherein the MCrAlYmaterial has the following composition: 18% by weight chromium, 10% byweight cobalt (Co), 6.5% by weight aluminum (Al), 6% by weight tantalum(Ta), 2% by weight rhenium (Re), 0.5% by weight hafnium (Hf), 1% byweight silicon (Si), 0.3% by weight yttrium (Y), the remainder beingnickel.
 7. The component as recited in claim 1, wherein the abrasiveparticles of the cover are made of cubic boron nitride.